. >> reporter: after back-to-back blizzards two years ago and the unforgettable wrath of superstorm sandy, mother nature is unleashing a winter storm so intense, the snowfall could be the worst in a century. the warnings could not be clearer. >> stay off the streets of our city. basically, stay home. >> reporter: a snowstorm that hit the great lakes with snow and ice is joining another storm in the south to form a monster nor'easter. as many as 23 million people are in the path. some coastal areas hit by hurricane sandy are in the bull's-eye of a prolonged storm. some of sandy's survivors still living in tents on new york's staten island will have to move. floods threaten the northeast shoreline for thousands of miles. it's a dreaded sense of deja vu. along the new jersey shore. >> i think i'm going to have to move my things upstairs and see what happens. >> in case it floods? yeah. >> reporter: salt truck and plow operators from pennsylvania to maine are ready for a long haul. >> it will probably be a long four days. you know? which is tough on anybody. >> reporter: fears of power outage